Rational design of the self-assembled BaCo1-xZrxO3-δ (x = 0.8–0.2) nanocomposites as the promising low/intermediate-temperature solid oxide fuel cell cathodes

Abstract Assembling multiple perovskites with complementary properties is a promising strategy to achieve high-performance cathodes for low/intermediate-temperature solid oxide fuel cell (LT/IT-SOFC). In this work, self-assembling perovskites of cubic BaZr0.82Co0.18O3-δ (cub-BZC) and hexagonal BaCo0.96Zr0.04O2.6+δ (12H-BC) at the nanoscale can be realized in novel designed nanocomposites with nominal composition of BaCo1-xZrxO3-δ (x = 0.8–0.2), which can possess congenital compatibility, improved thermal expansion coefficients and electrical conductivity. The relative contents of cubic and hexagonal phases are significantly correlated with the zirconium content (x). Therein, BaCo1-xZrxO3-δ nanocomposites exhibit relatively low content differences among perovskite phases when x = 0.4 (cubic/hexagonal = 62:38) and x = 0.2 (hexagonal/cubic = 69:31) nanocomposites, which can form more extensive heterointerfaces for promoting oxygen adsorption, dissociation and reduction reaction. When further applied as cathode, the cell with BaCo1-xZrxO3-δ nanocomposites achieve 2265–598 mW cm−2 (800–600 °C) when x = 0.2 as a promising IT-SOFC cathode, and 315−148 mW cm−2 (550–500 °C) when x = 0.4 as a promising LT-SOFC cathode.